%%%-------------------------------------------------------------------
%%% @author Anil Kumar S. R. <sranil@gmail.com>
%%% @copyright (C) 2010, 
%%% @doc
%%%
%%% @end
%%% Created : 16 Oct 2010 by Anil Kumar S. R. <sranil@gmail.com>
%%%-------------------------------------------------------------------
-module(media_session).

-behaviour(gen_server).

-include("../include/sip.hrl").

%% API
-export([start/1]).

%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
         terminate/2, code_change/3]).

%%%===================================================================
%%% API
%%%===================================================================

%%--------------------------------------------------------------------
%% @doc
%% Starts the server
%%
%% @spec start() -> {ok, Pid} | ignore | {error, Error}
%% @end
%%--------------------------------------------------------------------
start([SIP_Session_PID]) ->
    gen_server:start(?MODULE, [SIP_Session_PID], []).

%%%===================================================================
%%% gen_server callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Initializes the server
%%
%% @spec init(Args) -> {ok, State} |
%%                     {ok, State, Timeout} |
%%                     ignore |
%%                     {stop, Reason}
%% @end
%%--------------------------------------------------------------------
init([SIP_Session_PID]) ->
    {ok, #media_session_state{sip_session_pid = SIP_Session_PID}}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling call messages
%%
%% @spec handle_call(Request, From, State) ->
%%                                   {reply, Reply, State} |
%%                                   {reply, Reply, State, Timeout} |
%%                                   {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, Reply, State} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_call(create_media_socket, _From, State) ->
    io:format("Inside create_media_socket ~n"),
    case catch get_port_and_socket() of 
        {ok, {{RTP_Port, RTP_Socket}, {RTCP_Port, RTCP_Socket}}} ->
            {reply, {ok, RTP_Port}, State#media_session_state{rtp_socket = RTP_Socket, rtp_port = RTP_Port, rtcp_socket = RTCP_Socket, rtcp_port = RTCP_Port}}; 
        _ ->
            {reply, error, State}
    end;

handle_call(get_port, _, State) ->
    #media_session_state{rtp_port = RTP_Port} = State,
    {reply, {ok, RTP_Port}, State};

handle_call(_Request, _From, State) ->
    Reply = ok,
    {reply, Reply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling cast messages
%%
%% @spec handle_cast(Msg, State) -> {noreply, State} |
%%                                  {noreply, State, Timeout} |
%%                                  {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_cast({set_peer_address_and_media, {Peer_IP, Peer_Port}, Media}, State) ->
    {noreply, State#media_session_state{peer_ip = Peer_IP, peer_rtp_port = Peer_Port, peer_rtcp_port = Peer_Port + 1, media = Media}};

handle_cast(kill_process, State) ->
    {stop, normal, State};

handle_cast(_Msg, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Handling all non call/cast messages
%%
%% @spec handle_info(Info, State) -> {noreply, State} |
%%                                   {noreply, State, Timeout} |
%%                                   {stop, Reason, State}
%% @end
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
    io:format("Got Response ~n"),
    {noreply, State}.

%%--------------------------------------------------------------------
%% @private
%% @doc
%% This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
%%
%% @spec terminate(Reason, State) -> void()
%% @end
%%--------------------------------------------------------------------
terminate(_Reason, State) ->
    #media_session_state{rtp_socket = RTP_Socket, rtcp_socket = RTCP_Socket} = State,
    io:format("media_session terminated ~n"),
    gen_udp:close(RTP_Socket),
    gen_udp:close(RTCP_Socket).

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Convert process state when code is changed
%%
%% @spec code_change(OldVsn, State, Extra) -> {ok, NewState}
%% @end
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%%%===================================================================
%%% Internal functions
%%%===================================================================
get_port_and_socket() ->
    get_port_and_socket(100).

get_port_and_socket(0) ->
    error;

get_port_and_socket(Count) ->
    case catch port_manager:get_port() of
        {ok, RTP_Port} ->
            case catch create_socket(RTP_Port) of
                {ok, RTP_Socket} ->
                    case catch create_socket(RTP_Port + 1) of
                        {ok, RTCP_Socket} ->
                            {ok, {{RTP_Port, RTP_Socket}, {RTP_Port + 1, RTCP_Socket}}};
                        _ ->
                            gen_udp:close(RTP_Socket),
                            get_port_and_socket(Count - 1)
                    end;
                _ ->
                    get_port_and_socket(Count - 1)
            end;
        _ ->
            {error, "106"}
    end.

create_socket(Port) ->
    case catch gen_udp:open(Port, [binary, {active, once}, {reuseaddr, true}]) of
        {ok, Socket} ->
            {ok, Socket};
        _ ->
            error
   end.
